Aggregate Analysis of Health and Usage Monitoring System Data on Naval Rotorcraft

The Department of the Navy (DON) is installing variants of the Integrated Mechanical Diagnostic System (IMDS), a commercial, integrated airborne and ground-based health and usage monitoring system, on its fleet of rotary wing aircraft. In addition to providing aircraft systems monitoring and diagnostic capabilities, the IMDS is the principal data source for a knowledge management process evolving within the DON known as Military Flight Operations Quality Assurance (MFOQA). MFOQA provides actionable information to improve safety, training, maintenance, and operational efficiencies through the analysis and visualization of aircraft systems and flight performance data. This paper presents results from aggregate analyses of data collected from two rotorcraft types being equipped with IMDS within the DON, including the identification and trending of select MFOQA events of interest, assessments of aircraft operational usage, and comparisons of event occurrence rates for squadrons across a fleet of similar rotorcraft types. Distinct differences in operational usage of aircraft from training and non-training squadrons were found. Data show that training aircraft operate in low airspeed and low altitude ranges approximately twice the time of non-training aircraft as a percentage of total flight time, and operate with engine torque between 100% and 121% torque approximately half as much. These results are somewhat expected given the differences in aircraft weights, operating areas, and mission requirements. Training aircraft were also found to have an occurrence rate of high angle of bank exceedances at high airspeed almost 60% lower than non-training aircraft. Findings that were not necessarily expected include a 17% higher occurrence rate for training aircraft of G exceedances and an almost 48% higher rate of high angle of bank exceedance as a percentage of total flight time compared with non-training aircraft. In addition to comparisons between training and non-training aircraft, comparisons between detached aircraft (i.e., aircraft operating apart from their home command) and non-detached aircraft, and aircraft operating on the east and west coasts of the United States, were investigated. Finally, a heat map display was developed for displaying a detailed yet concise representation of results from analyses of aggregated data for comparisons of multiple squadrons, groups of squadrons, or individual aircraft.